The present invention relates to a feed roller assembly for a fax machine, and more particularly to such a feed roller assembly which permits the fed sheet of paper to be smoothly carried forwards by the transmission roller of the fax machine.
A fax machine comprises a feed roller driven to feed sheets of paper individually, and a transmission roller driven to deliver fed sheet of paper at a higher speed. Because the feed roller and the transmission roller are separately turned at different speeds, the fed sheet of paper may easily be jammed between the feed roller and the transmission roller. There is known a feed roller assembly equipped with a one-way coupling element and designed to eliminate the aforesaid problem. The one-way coupling element is fixedly mounted on the axle of the roller assembly and having a raised portion. The transmission gear of the feed roller assembly has a raised portion normally stopped at the raised portion of the coupling element. When the feed roller of the feed roller assembly is pulled by the transmission roller, the raised portion of the coupling element is disconnected from the raised portion of the transmission gear to eliminate the formation of a reverse active force. This structure of feed roller assembly is still not satisfactory in function. When a long sheet of paper is fed, the function of the one-way coupling element cannot be fully carried out, and the fed sheet of paper may be jammed in the fax machine, or delivered forwards at an uneven speed.